It is frequently necessary to provide communication between a plurality of users with the aid of telecommunication devices, a large number of telecommunication devices enabling communication between a plurality of conference participants. This communication is handled by means of a telecommunication conference system.
For the purposes of organized communication, a communication right for the transmission of a specific medium, for example audio data, video data or text data, is generally not allocated to all of the conference participants at the same time. The communication rights are allocated in accordance with specific rules, it being possible to control the allocation of communication rights using floor control and to control the rules using the floor policy in accordance with the Internet Engineering Task Force (IETF) standard.
The communication right for a communication medium, for example audio or video, is the right to transmit the communication medium. In other words, a communication right is the right to transmit a data stream for the chosen communication medium.
According to the prior art, systems which provide the conference participants with a plurality of microphones and loudspeakers for spoken communication are used in conference rooms. The microphone which is provided for a conference participant must be activated or switched on by the respective participant for communication. A microphone which has been activated or switched on blocks all the other microphones in the conference system, with the result that only one speaker or participant is ever active. According to one embodiment, a further microphone, for example that of a conference participant who is controlling the conference, may also be active. The communication right is only ever granted to one conference participant, and if required, to that conference participant who is controlling the conference.
According to the prior art, conference participants who are remote from one another can also communicate with one another by telephone or by means of a video conference, the participants being able to simultaneously transmit voice messages or other messages, that is to say, for example, messages using other media, in this case.
Comparable telecommunication conference systems and services likewise exist for mobile telecommunication devices, mobile telephones. One example of this is the “Direct Connect” PTT (push to talk) service from the company Nextel, which is known from the United States of America. In accordance with this service, a conference participant has to operate a key (which is designed for this purpose) on his mobile telephone, as in the case of “walkie-talkies”, for example, in order to transmit messages, the transmission of messages by other conference participants being blocked during this period of time and only one single conference participant thus being granted a communication right, for example for communication using voice or video data.
Telecommunication conference systems can also be controlled by means of more complex allocation of communication rights. For example, a conference participant may be granted a communication right following a communication right for another conference participant, or it is possible to provide for three and only three conference participants to be granted a communication right at the same time. In general and in this specific context, the communication rights can be allocated by a human or mechanical entity, the so-called moderator.
In accordance with the telecommunication systems of the prior art, communication rights can be allocated and granted for different communication means, for example audio data, video data or text data.
A method for so-called “conference floor control” based on the “Session Initiation Protocol” (SIP) and on the “Simple Object Access Protocol” (SOAP) is described in Wu et al., Use of Session Initiation Protocol (SIP) and Simple Object Access Protocol (SOAP) for Conference Floor Control, IETF Internet-Draft, draft-wu-sipping-floor-control-04.txt, March 2003.
According to Wu et al., control of a multimedia conference having a plurality of conference participants is improved. By way of example, floor control can be used to avoid or resolve conflicts which result from simultaneous communication media inputs by a plurality of conference participants. The signaling operation for setting up, modifying and clearing multimedia sessions between the telecommunication devices and the conference server device and the transmission of signaling data to other telecommunication devices or communication services servers are effected using the SIP (Session Initiation Protocol) specified by the IETF (Internet Engineering Task Force).
The characteristics of an SIP signaling process, that is to say of a signaling procedure according to the SIP which is implemented for an application, may be very different for different applications.
By way of example, the sizes of the SIP messages which are transmitted in an SIP signaling process, the frequency with which SIP messages are transmitted in a signaling procedure according to the SIP, and the transmission priority of individual SIP messages which are transmitted in an SIP signaling process may vary greatly. In the case of a voice communication link (session), SIP messages are transmitted, for example, when setting up the communication link, during the call (for example for the purpose of reconfiguring the communication link) and when ending the communication link.
In a multimedia conference having at least two telecommunication devices, the signaling processes are controlled by means of so-called SIP dialogs.
The SIP allows, in particular, a multiparty voice communication link, this voice communication link being based on a so-called “tightly coupled conference”, as described in J. Rosenberg, A Framework for Conferencing with the Session Initiation Protocol, IETF Internet-Draft, draft-ietf-sipping-conferencing-framework-02.txt, June 2004.
A tightly coupled conference is a conference in which a central functional unit, the so-called focus, is a mediator which interacts with each conference participant.
EP 1 006 706 A2 discloses a method and a system for setting up and controlling a secondary telephone conference in a main telephone conference, the system having a secondary conference system for providing a secondary telephone call, the system responding to a request for a secondary telephone conference, and the system transmitting the request for a secondary telephone conference from a first terminal to a second terminal during the main telephone conference. According to EP 1 006 706 A2, the telephone conferences are run using a WLAN (wireless local area network). The system also has a so-called “gatekeeper” which is set up to control the conferences and grants communication rights to the conference participants.
U.S. Pat. No. 5,440,624 discloses a method and a system for automatically running and controlling an electronic network conference. A defined but flexible rule base manages the conference which is implemented and evaluated by a conference control unit. The rule base is also automatically implemented by a conference administration system, that is to say the conference is managed taking into account the rule base in order to control the allocation of communication rights, a conference control unit controlling the network conference.
U.S. Pat. No. 5,483,588 discloses a telephone conference system having a conference control unit which eliminates the need to control the telephone conference using a human operator.
G. Camarillo et al, The Binary Floor Control Protocol (BFCP), IETF Internet-Draft, draft-ietf-xcon-bfcp-02.txt, October 2004 describes the Binary Floor Control Protocol (BFCP) which is to be used for “conference floor control” in a conference system in accordance with the IETF.
A communication system 100 according to the prior art will be described below with reference to FIG. 1, the architecture being in the form of a star.
The communication system 100 also has a communication server device 101 as well as a multiplicity of telecommunication terminals which are set up as mobile radio terminals in accordance with this exemplary embodiment and are generally referred to below as telecommunication devices (in accordance with this exemplary embodiment, a first telecommunication device 102, a second telecommunication device 103, a third telecommunication device 104 and a fourth telecommunication device 105), a signaling link 106 between the communication server device 101 and the first telecommunication device 102, a signaling link 107 between the communication server device 101 and the second telecommunication device 103, a signaling link 108 between the communication server device 101 and the third telecommunication device 104, a signaling link 109 between the communication server device 101 and the fourth telecommunication device 105, a first conference participant 110 who is associated with the first telecommunication device 102, a second conference participant 111 who is associated with the second telecommunication device 103, a third conference participant 112 who is associated with the third telecommunication device 104, and a fourth conference participant 113 who is associated with the fourth telecommunication device 105.
The communication system 100 is embodied in accordance with the UMTS architecture described by 3GPP.
Current push to talk (PTT) systems and conference systems according to the prior art have the disadvantage, in particular, that the communication rights can be allocated using one and only one moderator unit. If the allocation of the communication right is to be decided using a plurality of moderator units, this decision must be made using means which are outside the conference. In other words, this means that the decision on the allocation of the communication right is made using an implementing moderator unit which is outside the conference and is thus not directly part of the conference. The conference is then informed of the decision, in which case this operation of informing the conference is not effected automatically and the process of coming to a decision may require lengthy discussions.
Document U.S. Pat. No. 5,680,392 describes a method for reserving radio resources for a conference, in which a user sends a request for the provision of radio resources which are required for the conference. A plurality of control units determine whether they can provide radio resources required for the conference and inform a master reservation unit of the result. The master reservation unit informs the user of whether the radio resources which are required for the conference are available.
Document US 2004/0057449 discloses a method for providing group communication for a group of communication terminals. The communication terminals send data packets (which need to be transmitted) to a communication management unit which operates as a switch and forwards the data packets.
US 2004/0047461 describes a conference system having a conference server unit. The conference server unit manages a conference and undertakes the task of media mixing, for example. A moderator can control who may participate in a conference.